Published: 18 Jun 2025

ICD9: 042      ICD10: B20      ICD11: 1C62.Z

HIV (Human Immunodeficiency Virus) is a virus that attacks the body's immune system, specifically the CD4 cells (T cells), which help the immune system fight off infections.
If left untreated, HIV can lead to AIDS (Acquired Immunodeficiency Syndrome).

Here's a breakdown:

HIV (Human Immunodeficiency Virus): This is the virus itself. It infects and destroys CD4 cells, weakening the immune system.

How HIV Works: The virus enters CD4 cells and uses them to make copies of itself. This process eventually kills the CD4 cells, reducing their numbers in the body.

Progression of HIV: HIV infection progresses in stages. Early infection may have flu-like symptoms, or no symptoms at all. As the infection progresses and CD4 cell counts decline, the risk of opportunistic infections (infections that wouldn't normally affect someone with a healthy immune system) increases.

AIDS (Acquired Immunodeficiency Syndrome): This is the most advanced stage of HIV infection. It's diagnosed when the CD4 cell count drops below a certain level (200 cells per cubic millimeter of blood) or when specific opportunistic infections or cancers develop. AIDS represents severe damage to the immune system.

Transmission: HIV is transmitted through specific bodily fluids:

Blood
Semen and pre-seminal fluid ("pre-cum")
Rectal fluids
Vaginal fluids
Breast milk

The most common ways HIV is spread are:

Unprotected sex (vaginal, anal, or oral)
Sharing needles or syringes
From mother to child during pregnancy, childbirth, or breastfeeding (this is preventable with treatment)

HIV *cannot* be spread through:

Air or water
Saliva, sweat, or tears
Shaking hands or hugging
Casual contact
Sharing toilets or utensils

Symptoms:
*Early Stage (Acute HIV Infection):* Many people don't have any symptoms. Some may experience flu-like symptoms such as fever, headache, rash, sore throat, and swollen lymph nodes.
*Clinical Latency (Chronic HIV Infection):* The virus is still active but reproduces at low levels. People may not have any symptoms during this period, which can last for many years with treatment. Without treatment, this phase can last for up to a decade, but some progress faster.
*AIDS:* As the immune system becomes severely damaged, people develop opportunistic infections, cancers, and other conditions. Symptoms can include:
Rapid weight loss
Extreme tiredness
Recurring fever or night sweats
Swollen lymph nodes
Diarrhea that lasts for more than a week
Sores of the mouth, anus, or genitals
Pneumonia
Memory loss, depression, and other neurological disorders

Treatment: There's no cure for HIV, but antiretroviral therapy (ART) can control the virus and prevent progression to AIDS. ART involves taking a combination of medications that suppress the virus, allowing the immune system to recover and preventing further damage. With effective ART, people with HIV can live long and healthy lives and have a dramatically reduced risk of transmitting the virus to others. People on ART can achieve and maintain an undetectable viral load (the amount of HIV in their blood). Undetectable = Untransmittable (U=U).

Prevention: There are several ways to prevent HIV transmission:

Testing: Get tested regularly for HIV.
Condoms: Use condoms consistently and correctly during sex.
PrEP (Pre-exposure prophylaxis): Taking a daily pill (PrEP) can significantly reduce the risk of HIV infection in people who are HIV-negative and at high risk.
PEP (Post-exposure prophylaxis): If you think you've been exposed to HIV, taking PEP (a course of antiretroviral medication) within 72 hours of exposure can prevent infection.
Treatment as Prevention (TasP): People with HIV who take ART and achieve and maintain an undetectable viral load cannot transmit the virus sexually.
Clean Needles: Never share needles or syringes.
Safe Blood Supply: Screening of blood donations has made the blood supply very safe.

Importance of Early Diagnosis and Treatment: Early diagnosis and treatment with ART are crucial. They allow people with HIV to live longer, healthier lives and reduce the risk of transmission to others.

In summary, HIV is a virus that attacks the immune system and can lead to AIDS. While there is no cure, effective treatments are available to control the virus, prevent progression to AIDS, and allow people with HIV to live long and healthy lives. Prevention strategies are also available to reduce the risk of HIV transmission. If you have concerns about HIV, talk to a healthcare provider.